refactor(crm order item): 移排序逻辑到后端并简化前端代码

1. 将原前端的分组排序逻辑迁移到后端service实现
2. 后端实现三级排序：交货日期倒序→订单ID升序→创建时间倒序，保证跨页排序一致性和合同组连续排列
3. 移除前端冗余的groupSort方法和排序状态变量，简化前端页面逻辑
4. 更新前端排序提示文案为固定描述

klp-ui/src/views/crm/orderItem/index.vue

@@ -76,7 +76,7 @@
       />
       <el-button type="primary" size="small" icon="el-icon-search" @click="handleQuery">筛选</el-button>
       <el-button size="small" icon="el-icon-refresh" @click="resetQuery">重置</el-button>
-      <span v-if="sortInfo" class="sort-hint">{{ sortInfo }}</span>
+      <span class="sort-hint">已按合同交货日期倒序 + 明细创建时间倒序排列</span>
     </div>
 
     <!-- 订单明细表格 -->
@@ -345,9 +345,7 @@ export default {
       // 存储原始数据，用于判断是否有修改
       originalData: {},
       // 表面处理选项
-      surfaceTreatmentOptions: [],
-      // 排序状态提示
-      sortInfo: ''
+      surfaceTreatmentOptions: []
     }
   },
   created() {
@@ -382,7 +380,7 @@ export default {
           // 批量获取合同信息
           this.loadContractInfo(orderIds, items)
         } else {
-          this.orderItemList = this.groupSort(items)
+          this.orderItemList = items
           this.loading = false
         }
       }).catch(e => {
@@ -405,8 +403,8 @@ export default {
         contracts.forEach(contract => {
           this.contractMap[contract.orderId] = contract
         })
-        // 合并数据
-        const merged = items.map(item => {
+        // 直接合并数据（后端已按 deliveryDate DESC + createTime DESC 排序）
+        this.orderItemList = items.map(item => {
           const contract = this.contractMap[item.orderId] || {}
           return {
             ...item,
@@ -417,8 +415,6 @@ export default {
             deliveryDate: contract.deliveryDate || ''
           }
         })
-        // 排序后赋值
-        this.orderItemList = this.groupSort(merged)
         // 保存原始数据副本
         this.originalData = {}
         this.orderItemList.forEach(row => {
@@ -426,53 +422,12 @@ export default {
         })
       }).catch(e => {
         console.error(e)
-        this.orderItemList = this.groupSort(items)
+        this.orderItemList = items
       }).finally(() => {
         this.loading = false
       })
     },
 
-    // 分组排序：组间按交货日期倒序，组内按创建时间倒序
-    groupSort(items) {
-      if (!items || items.length === 0) {
-        this.sortInfo = ''
-        this._groupColorIndex = 0
-        return items
-      }
-      // 构建每个orderId对应的deliveryDate映射
-      const deliveryDateMap = {}
-      items.forEach(item => {
-        if (item.orderId && !deliveryDateMap[item.orderId]) {
-          deliveryDateMap[item.orderId] = item.deliveryDate || ''
-        }
-      })
-      const sorted = [...items].sort((a, b) => {
-        // 同组：按createTime倒序
-        if (a.orderId && a.orderId === b.orderId) {
-          const timeA = a.createTime || ''
-          const timeB = b.createTime || ''
-          if (timeA === timeB) return 0
-          if (!timeA) return 1
-          if (!timeB) return -1
-          return timeB > timeA ? 1 : -1
-        }
-        // 异组：按deliveryDate倒序
-        const dateA = deliveryDateMap[a.orderId] || ''
-        const dateB = deliveryDateMap[b.orderId] || ''
-        if (dateA === dateB) {
-          // 交货日期相同或都为空时，按orderId排序保证分组连续
-          return (a.orderId || 0) - (b.orderId || 0)
-        }
-        if (!dateA) return 1
-        if (!dateB) return -1
-        return dateB > dateA ? 1 : -1
-      })
-      // 设置排序状态提示
-      const groupCount = Object.keys(deliveryDateMap).length
-      this.sortInfo = `已按合同交货日期倒序 + 明细创建时间倒序排列（共${groupCount}个合同组）`
-      return sorted
-    },
-
     // 分组行样式：同一合同组使用交替背景色
     groupRowClassName({ row, rowIndex }) {
       // 记录上一个orderId，切换时翻转颜色